Hot top



Nov. 18 1941. CAMERON 2,263,437

HOT TOP Filed April 11, 1940 INVENTOR. JOHN 3. CA NEPON Patented Nov. 18, 1941 HOT TOP John B. Cameron, Massillon, Ohio, assignor to Republic Steel Corporation, Cleveland, Ohio, a corporation of New Jersey Application 'April 11,1940, Serial No. 329,130 1 Claim. (01. 22-147) This invention relates to improvements in hot tops, and more particularly to a hot top for an ingot mold which increases the ingot yield and reduces the amount of cropping necessary to remove the piped portions of the ingot.

As is well known in the industry, when the ingots are poured it is desirable to maintain the upper portion of the ingot in the molten state as long as possible to permit the gases in the molten steel to escape and not become entrapped in the ingot body. These gases rise through the molten steel and if the steel solidifies before they have escaped, they form cavities in the body of the ingot.

These cavities may very well occur at some place in the ingot where they will not be removed with the cropping, and may not show up except in the finished product. Obviously such cavities will render the product unfit for service. Although hot tops are wellknown and to a considerable extent tend to allow these gases to escape, they are by no means perfect, and have various disadvantages. .Among the disadvantages, due to the use ofordinary hot tops, is the loss of metalfrom the top of the ingot necessary due to cropping to remove the piped portion of the ingot. Not only is the area of the crop relatively large due to the diameter of the crop, but the cavities, called pipe, often extend a considerable distance into the body of the ingot.

It is therefore an object of this invention to increase in efficiency is efie d by maintaining v.end of an ingot mold showing the hot top of my invention in place and ready for teeming;

Figs. 2 and 3 are contour views of the upper portions of two ingots, Fig. 2 representing an ingot poured with the usual type of hot top, and

Fig. 3 of an ingot where the hot top of my inthe height of the metal in the hot top, but reducing it in cross section; providing additional insulation at certain points where it is vital that the ingot stay molten; and provide for a full floating of the hottop with adjustments so that the height can be increased or decreased as desired.

Another important feature of the invention is to provide a hot top that is easily and economically constructed; and that is also convenient in use, being made in two .parts that enable the same to betassembled on the ingot without the aid of special handling equipment, and wherein vention was used.

Referring now to the drawing throughout which like parts have been designated by like reference characters, and more particularly to Fig. 1, there is represented, in section, the upper end I of an ingot mold which may be any of the types in common use, and where it is good practice to use a hot top. The upper end of the mold, as is the usual case is provided with a fiat surface 2 upon which the hot top may be supported. The hot top is formed in two parts and includes a lower base member 3 of refractory material and an upper member 4 also formed of like material.

The base 3 has a wall 5 which may be of a thickness proportional tothe size of the mold and the periphery of which conforms to the cross sectional contour of the mold. That is, if the ingot mold is squ re, the wall body is square, and.

if the mold is r und or fluted, the wall is similarly shaped. The wall is provided with a plurality of outwardly extending lugs 6 which may rest on blocks '1 interposed between the lugs and the top edge of, the mold to support the hot top in any desired position on the mold. The

. thickness of the block I may be varied to raise or lower the base in the mold. The diameter of the base is smaller than the inside of the mold to provide an air gap 8 between the hot top and -lar shape and construction to the base member,

comprising a body HI contoured like the inner surface of the base and ot a smaller diameter,

to provide an air space H therebetween. The body is provided with outwardly extending supporting lugs l3 adapted for engagement with the upper edge of the base member. These lugs, as

in'the case of the base, are spaced off-center from the ends of the member so that by reversing the upper member the body may extend a greater or lesser distance intothe lower base part, the alternate position being shown by the dotted lines. The ends of the body are beveled at H and I5 toward the interior to eliminate sharp edges and prevent chipping of the edge during pouring, which chips might fall into the mold.

The inner surface of the base member does-not necessarily have to follow the contour of the periphery but may be made circular in cross section. In this construction a single type of upper feeder members may be used in conjunction with lower base members of various contours, thus lessening the variety of parts necessary to becarried in stock.-

It will thus be seen that I have provided a hot top which is simple and-economical to manufacture because the two separate parts are of relatively simple construction: It is also to be noted that the greatest amount of insulation is disposed at that point of the ingot where it is most needed to prevent the bridging-over by solidifying metal at the top of the, ingot, maintaining the ingot molten near the top to allow a greater period of time for the escape of gases from the body of the ingot reducing the area of pipe. For instance, the lower part of the base member extends into the mold, but is spaced therefrom by the air space 8, which allows gases to escape as well as affording additional insulating properties. The upper member also extends down into the lower member overlapping the lower member in this critical zone, affording a double thickness of insulation at the point where the bridging-over normally occurs. The space ll between the upper and lower parts affords additional insulation and opportunity for the escapeaof gases.

Figs. 2 and 3 are diagrams made from actual photographs of cross sections of crops of ingots which have been teemed with the ordinary type of hot top and with my improved hot top respectively. It is to be noted in Fig. 2 that the piping is dispersed throughout the area of the crop, showing that the crop was cooling so fast that the gas was not readily escaping.

Fig. 3 illustrates the piping with the hot top of my invention showing that the piping was confined to-one space; this illustrates how the metal weight of entire hot top.

yet the gas was free to escape. It should also be noted that, although the crop is higher, it is of materially less diameter and that therefore there is actually considerably less metal in the crop and hence a greater yield in the ingot. Actual figures have shown that there is a saving in yield of from 2.1% to 3%.

Being in two parts, the hot top is easier to handle due to less weight of each part and decreased Where in the past a crane has been necessary in some instance to install the other hot tops on the mold, this crane work may be eliminated and the hot tops installed by hand. This two-part feature also has other advantages than that of lightness, among these I being that of manufacture previously mentioned, and the fact that there is less breakag because This improved hot top also lends itself peculiarly to adjustment of the ingot for volume, and

' insures greater accuracy of center pouring during teeming. Its incr sed height assists in segre- 25 gating the pipe, and due to less cross sectional area does not increase the volume and so reduces loss due to cropping. v

The term annular wall as used herein refers to the upper and lower refractory members and means that these walls are circumferentia'lly continuous and not necessarily that they are circular. In fact many ingot molds are substantially rectangular in cross section and the hot tops are also rectangular. Other molds are hexagonal or octagonal in cross section and their hot tops Having thus described'my invention, I claim: V

A hot top for an ingot mold comprising upper and lower refractory members telescopable with relation to each other and with an ingot mold,

5 each member having an annular wall conforming to the cross sectional contour of an ingot mold and supporting lugs projecting outwardly from said walls, the lugs of th upper member resting on the top of the lower member and the lugs of the lower member resting on the top of the mold,

there being an annular space between the mold and the annular wall of the lower member and an annular space between the annular walls of f the two members.

JOHN B; CAMERON; 

